This invention relates to a video instrument that is equipped with a needle-like probe capable of being inserted into an extremely small opening to provide a full color video image of an ordinarily inaccessible target and, in particular, to a medical instrument that includes a needle-like probe that can be passed through a small surgical incision to view a specific target inside the body as for example the interior of the eye.
Needle probes have been used in the medical art for some time for viewing interior parts of the body. When using these probes, however, the target can be viewed through an eye piece by only one person. Furthermore, the degree of control over the instrument is extremely limited because the user must maintain his eye aligned at all times with the eye piece. These direct viewing instruments do not lend themselves for use in ophthalmology because of the high risk of the probe contacting delicate parts of the inner eye. Adapting a camera for use in conjunction with a needle probe has also proven to be unsatisfactory because the weight and size of the camera makes control of the probe difficult and poses a certain danger to the patient.
The use of needle probes equipped with coherent fiber bundles as described in U.S. Pat. No. 4,607,622 represent an advancement in the art, however, the resolution of the images produced are not of the highest quality because of the inherent limitations found in fiber bundles.
It is often necessary to perform microsurgery on the human eye, but there has been no high resolution instrument previously proposed which permits a surgical instrument to be safely introduced into the eye for viewing and control of the instrument within the eye. Observation of the delicate surgical maneuvers is carried out by viewing through the eye's crystalline lens. This can be quite difficult in cases where the view is obstructed, i.e. in cataract or glaucoma patients, or where the injured or diseased tissues are disposed well away from the main axis of the eye.
Endoscopes are diagnostic devices which carry a viewing head at the end of an elongated insertion tube. These are widely used for examination of tissues within body cavities such as the colon and esophago-gastric tract. However, because the minimum size of the viewing head is rather large, i.e., on the order of 5 mm or larger in diameter, it has previously been impossible to insert an endoscope type instrument into a small, delicate organ such as the eye.
Various endoscopes are described, for example, in U.S. Pat. Nos. 4,491,865; 4,074,306; and 2,764,149.